Conventional technology discloses a method for processing multiple camera images of vehicle surroundings for display to the driver as described in, for example, FIG. 7 of Japanese Kokai Patent Application No. 2004-254219. The vehicle surrounding image-processing device described in that reference provides an image (a bird's-eye view image hereafter) from pickup devices mounted on the vehicle by converting one or more camera images into an image as if picked up from an imaginary overhead viewing point by coordinate transformation with respect to a reference plane and superimposing a computer-generated image of the vehicle prepared beforehand with computer-generated technology on the images. During the preparation of such a bird's-eye view image, the ground surface is often used as the reference plane. Since the positional relationship between the white line, the curb, etc., on the ground surface and the vehicle is expressed objectively, this bird's-eye view image is an effective aid when parking in a marked parking space or when moving the vehicle alongside a curb.